toit de la formation

CONT: En l'absence d'hypothèses supplémentaires, sur la nature des formations, leur chronologie, et leurs relations il est difficile de dessiner une coupe qui ait un sens géologique. Par contre si l'on fournit une chronologie et une suite de relations sur les formations on peut déterminer des toits de formation pertinents. Le toit d'une formation ne correspond pas nécessairement au sommet de la passe de cette formation rencontrée dans le sondage.
CONT: Profondeur du toit de la formation.
CONT: Aquifère gréseux du Néocomien à pendage de 35° vers l'ouest. Le point d'émergence se situe au toit de la formation à son contact avec les marnes du Cénomanien.

CONT: A list of all the important formation tops picked in the well by the petroleum geologist. Notice there are two numbers for each top. The first number is the actual measured depth in feet from a fixed elevation reference point on the rig (usually the KB, or Kelly Bushing, which is located about 1 feet above the derrick floor). The second number has a minus (-) sign in front of it. This is the calculated depth of the formation top in relation to the permanent datum, which is usually sea level. This type of top is known as a ""subsea"" top. Subsea tops can be easily compared to each other because they are all adjusted to the same elevation reference.
CONT: Formation Tops: Indicate the footage to tops (T) or bottom (B) of the formations penetrated by this well. The geological or engineering department usually supplies this information, which is taken from the mudlogger, or the well logs.
CONT: The tops of formations are shown only within the limits of borehole data and are shown with solid lines (Figure 17).